Conventionally, a steel crawler has been mainly applied to the traveling unit of a mobile construction machine, and a rubber shoe has been partially applied thereto. Recently, however, a rubber crawler is preferably used.
FIG. 22 is an explanatory view to describe an example of a conventional steel crawler: 101 is an outer flanged rolling wheel, 102 is a crawler shoe, 102a is a shoe plate, 102b is a track link, 102c is a linkage pin, and 102d is a lug (steel made). FIG. 23 is an explanatory view to describe an example of a rubber shoe: 103 is a rubber shoe, 103a is a shoe plate, 103b is a track link, 103c is a linkage pin, 103d is a rubber lug. FIG. 24 is an explanatory view to describe a conventional rubber crawler: 104 is a rubber crawler, 104c is a lug, 105 is a core metal, and 106 is a steel cord. In FIGS. 22-24, the same outer flanged rolling wheel can be used.
A steel crawler, wherein the upper surface of track links serves as a continuous track for a rolling wheel, effects small vibrations during traveling. Besides, it scarcely deviates from the wheel because of no elongation nor side displacement of the crawler in a circumferential or width direction. Moreover, it is excellent in durability because of strong mechanical connection between the links. However, it causes big noise and gives heavy fatigue to a driver because of its poor cushioning ability. In addition, it damages roads.
On the contrary, a rubber crawler effects small noise and has good cushioning ability without damaging roads. Besides, it is relatively lightweight so as to drive at high speed. However, it causes somewhat strong driving vibrations because an upper face of a projection of each core metal serves as a wheel track. In addition, when it receives big outer pressure in its circumferential or width direction, which causes elongation and side displacement, it deviates from the wheel. Moreover, it is inferior to the steel crawler in mechanical strength and durability.
A rubber shoe, wherein a rubber lug is provided on the ground side of a shoe plate of a steel crawler, has such structural problems that the shoe plat is apt to come off the rubber lug, and that the rubber lug is easily damaged or worn down because it is pressed between the shoe plate and the ground without any space for escape. Besides, a method of vulcanizing and fixing a rubber lug to each shoe plate highers the cost considerably. Accordingly, it can not be superior to a rubber crawler.
Therefore, an object of the present invention is to overcome the above demerits of the rubber crawler by adapting a structure of a steel crawler with its merits.